Field of the Invention
The invention relates to a semiconductor device, and more particularly, to a memory device.
Description of Related Art
In a memory device, to achieve the objects of increasing the channel length of the transistor, sufficiently utilizing substrate space, and increasing the distance between the wires in different layers, embedded wires are often formed in the substrate. To protect the embedded wires from being affected in a subsequent process, a cap layer is generally disposed above the embedded wires to protect the embedded wires. However, voids often appear in the cap layer, and therefore the protective function of the cap layer is significantly reduced.